Heretofore, low reflection glass plates have usually been prepared by the following methods (see, for example, JP-A-2002-194295). That is:
(1) A method for preparing a low reflection glass plate by laminating a multi-layer film utilizing optical interference, wherein the multi-layer film is obtained by laminating high refractive index materials such as titanium oxide and low refractive index materials such as silicon oxide on a glass substrate by a vacuum film-forming method or a vapor phase method such as sputtering while controlling refractive indices and film thicknesses so as to make interfaces between the films distinct.
(2) A method for preparing a low reflection glass plate utilizing optical interference, which comprises laminating at least two layers consisting of light absorption materials such as titanium nitride and low refractive index materials such as silicon oxide on a glass substrate by a vapor phase method such as sputtering while controlling refractive indices and film thicknesses so as to make interfaces between the films distinct,
(3) A method for preparing a low reflection glass plate utilizing optical interference, which comprises laminating at least two layers consisting of high refractive index materials such as titanium oxide and low refractive index materials such as silicon oxide on a glass substrate by a sol-gel method using a metal alkoxide, etc. while controlling refractive indices and film thicknesses so as to make interfaces between the films distinct, and
(4) A method for preparing a low reflection glass plate utilizing optical interference, which comprises laminating at least two layers consisting of high refractive index materials such as titanium oxide and low refractive index materials such as silicon oxide on a glass substrate by a sol-gel method using an aqueous metal ion-containing solution, a metal alkoxide, etc. while controlling refractive indices and film thicknesses so as to make interfaces between the films distinct.
Further, the above prior art has various problems as mentioned below, and as a method for solving these problems, the present inventors have proposed a process for producing a low reflection glass plate having a low reflectance and excellent abrasion resistance, chemical resistance, etc., by a process-wise advantageous method of applying a coating liquid, drying and baking (see, Japanese Patent Application 2002-359976). Further, a method for forming a colored baked film having excellent chemical resistance on a glass substrate, has been proposed (see, JP-A-10-231145).
However, the above vacuum film-forming method or the sputtering method requires large-scale equipment, and therefore there is a problem that the cost tends to be high. Further, a low reflection glass plate utilizing optical interference, which is prepared by a sol-gel method using e.g. a metal alkoxide, has a problem of deterioration in productivity because high temperature drying is required after applying a treating fluid on each layer so as to make interfaces between the films distinct.
Further, a low reflection glass plate having a low reflectance and excellent abrasion resistance, chemical resistance, etc., which can be obtained in the method proposed by the present inventors, has excellent low reflecting properties against light at a specific incident angle of 5°, but does not have a sufficient effect of reducing reflectance against light at other incident angles e.g. at an incident angle of 60°.
Accordingly, the first object of the present invention is to overcome the problems of the above prior art, and to provide a low reflection glass plate having low reflectance and excellent abrasion resistance, chemical resistance, etc., preferably showing a transmission color of blue, with good productivity.
Further, the second object of the present invention is to provide a low reflection glass plate having a sufficient effect of reducing reflectance against light at an incident angle of 60°, with good productivity.